The goal of the research is to determine the structure of eukaryotic (rat liver) ribosomes and to understand how the structure accounts for their function in protein synthesis. The specific aim is to determine the sequence of amino acids in rat ribosomal proteins by a combination of recombinant DNA technology and protein chemistry. We intend to prepare a library of cDNA clones specifying rat ribosomal proteins and sequence the DNA in order to deduce the structure of the proteins. In addition, we shall continue with the direct determination of the amino acid sequence of selected ribosomal proteins. Finally, we shall attempt to determine the mechanism by which the cytotoxin ricin inactivates eukaryotic ribosomes.